1. Field
Embodiments of the present invention relate to a thin film transistor array panel.
2. Description of the Related Art
A flat panel display, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an electrophoretic display, and a plasma display, includes a plurality of pairs of field generating electrodes, and electro-optical active layers therebetween. The LCD includes a liquid crystal layer as the electro-optical active layer, and the OLED display includes an organic emission layer as the electro-optical active layer. One of the field generating electrodes, of a pair of electrodes, is generally connected to a switching element to receive an electric signal, and the electro-optical active layer converts the electric signal into an optical signal to display an image.
A display panel including a thin film transistor may be included in the flat panel display. Many layers of electrodes, a semiconductor, and the like are patterned on a thin film transistor array panel, and a mask is generally used during a patterning process.
Meanwhile, a composition or structure of the semiconductor may determine a characteristic of the thin film transistor. Amorphous silicon is frequently used in such a semiconductor, but there are limits on the manufacturing of a high-performance thin film transistor including amorphous silicon due to low charge mobility in the amorphous silicon. Further, in the case of using polysilicon (e.g., polycrystalline silicon), due to high charge mobility of the polysilicon, the high-performance thin film transistor is easily manufactured, but there are limits on manufacturing a large-sized thin film transistor array panel due to high cost and low uniformity.
Accordingly, researches have been conducted for a thin film transistor using (utilizing) an oxide semiconductor, which has higher electron mobility and a higher on/off rate of current than amorphous silicon, and has a lower cost and higher uniformity than polysilicon.
To improve electron mobility of the thin film transistor, a material of the semiconductor may be changed or a channel width of the thin film transistor may be increased.
However, the increase of the channel width of the thin film transistor causes an increase of the size of the entire thin film transistor, and accordingly, an aperture ratio may be deteriorated during a manufacturing process of a display device.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.